1. Field of the Invention
The present invention relates to an electric power generator in an independent line which operates off mechanical energy picked up from a fluid which circulates in a pipe. The present invention has applications in gas and/or fluid transport and distribution networks by means of pipelines, in ocean platforms, in underwater sites, and in hydrocarbon production sites, in agricultural applications, and in general, in all sites where electricity is needed and where mechanical energy in the form of a fluid under pressure is available.
2. Discussion of Background
At many agricultural or industrial sites, mechanical energy is available in the form of liquid or gas fluid which circulates in a pipeline. At these sites, electricity is needed to provide power to equipment used for remote measurement, remote control, telecommunications, or air conditioning, etc. The local production of electric power is particularly advantageous at isolated sites in order to avoid laying electric cables to deliver electric power which could be expensive or technically unfeasible.
The invention described in French patent 2,686,376 provides for the conversion of mechanical energy of a moving fluid into electricity using a turbo-alternator driven by a gas, liquid, or gas/liquid mixture which circulates in a pipeline. The turbo-alternator is made up of a one-piece assembly that includes an angular turbine whose wheel is one piece in rotation of the alternator rotor. It also includes bearings in an airtight and equipressure mechanical joint which keeps motor fluid separate from oil used for bathing the rotor. The rotor of the alternator is placed outside the pipeline and is embedded in a circuit cooled by oil under pressure. The motor fluid input and output shafts are perpendicular, making the installation of the generator in a straight section of the pipeline impossible.
The above-described generator, in order to be usable with a fluid under high pressure, must include a body with very thick walls in order to resist the pressure. This results in a very heavy and very expensive assembly unit and in some applications such as oil production at sea, the weight of the equipment is a determining factor since expensive infrastructures may be needed to support the equipment. For this reason, a delicate vertical support is needed as a source to prevent vibration and wearing of the bearings and of the sealed mechanical joint. Consequently, monitoring is required with frequent maintenance and/or short operating lifetime making the generator quite costly to operate and build.
The above-described generator also includes feedthroughs for cables and an external oil cooling circuit. This complicates the installation and creates the risk of fluid leakage under pressure. For some applications in which the fluid is dangerous because of its toxicity and/or its flammability, this above-described generator does not offer sufficient safety guarantees.